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There's also the opposite effect, a windows security update broke GTA San Andreas because it relied on undefined behavior.

https://silentsblog.com/2025/04/23/gta-san-andreas-win11-24h...

by icase6 hours ago|

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in this dark age of agents writing code that gets debugged by other agents, i love reading stuff like this: stories of human intuition fixing human mistakes. thanks for a fascinating read.

by Cthulhu_11 hours ago|

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It feels like graphics drivers do / did this a lot too. At the very least they make specific optimizations for specific games, probably by tweaking settings and features that the game developers didn't optimize properly themselves.

by kalleboo11 hours ago|

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Famously if you renamed Quake 3 to "Quack" 3, it would slow down on the ATI Radeon 8500 https://web.archive.org/web/20091016055550/https://hardocp.c...

by account4210 hours ago|

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That's a case of the driver cheating but there are also lots of cases where the game is just full of bugs that the driver has to work around in order to not be blamed for them.

by smallstepforman3 hours ago|

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The driver switched to lower mipmapped texture and got caught. There is a ton of that out there for popular benchmark ready games. Run pro drivers instead of adrenaline to run generic baseline real driver.

by Gibbon110 hours ago|

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I've said over the years a few times, this isn't our fault but it's our problem.

by SyzygyRhythm10 hours ago|

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There are many, many, cases like this, including correctness fixes. One recent example I remember had a shader that computed: x = a / b * b

The optimizer was allowed, but not obligated, to transform that into: x = a

However, in this case, b was sometimes 0. And if so, the unoptimized version computed: x = a / 0 * 0 = Inf * 0 = NaN

So badness ensued if the that particular path didn't get optimized, which could happen under various circumstances. We had to add some code to ensure that transformation always happened on that game.

by DarkUranium8 hours ago|

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I'm curious, what's the ratio of:

- deciding to inform the game developer & wait for reply vs not waiting for reply vs just fixing it yourself without informing the developer; and

- if informed: developer actually fixing it vs only saying they would fix it vs no reply whatsoever (not counting automated "thank you for your inquiry" replies, in cases where you don't already have more direct channels to the dev than email)

I've always kind of wondered this because in a way, it's kind of weird that it's fixed for them, at least for new releases / games actively being developed.

(Full disclosure: I'm a game developer myself, with a very high interest in engine plumbing & dev [including graphics], though finding a job for the latter is easier said than done.)

by rbits3 hours ago|

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Yep. I know the Minecraft optimisation mod Sodium has encountered some issues because Nvidia drivers try to optimise the game in ways that can cause issues for them

by easyThrowaway11 hours ago|

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The most interesting part is that IIRC they shipped the entire Windows 3.11 memory allocator to make it work.

I have very little understanding on how allocation works at OS level, but I'm surprised there are no wrappers like dgVoodoo or dxWrapper specifically for this kind of issues. There are quite a bunch of old Windows games (Need for Speed 1-4 for a start) that refuse to run on modern OSes due to rather...bold memory management strategies.

by rincebrain11 hours ago|

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Apparently the recollection of the fix was that they deferred actually freeing memory for a while if they detected it was SimCity running. [1]

[1] - https://www.joelonsoftware.com/2000/05/24/strategy-letter-ii...

by DonHopkins10 hours ago|

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A story I heard at Sun, which may be apocryphal but was fucking hilarious enough to be a repeatable rumor, was that a release of an early operating system in BETA was determined to be solid and tested and ready to release and ship to customers, so they simply changed the version string from something like "SunOS2.1BETA" to "SunOS2.1FCS" (First Customer Ship), and recompiled. But the change from a 12 character version to an 11 character version threw off the alignment of some important data structures somewhere in the kernel, and the entire OS ran MUCH SLOWER because of 68k unaligned memory accesses!